Vascular Anesthesia pt3.2

Question 1

ROTEM/TEG Review Cards

Answer 1

Analyzes clot strength, formation and fibrinolysis

Question 2

Which type of evokes would be useful for tracking any damage to the dorsal column?

Answer 2

SSEP’s

Sensory = Dorsal column

Question 3

Which part of the spinal cord is typically more damaged by aortic clamping?

Answer 3

Anterior portion of spinal cord

MEPs = impractical due to NMBD usage.

Question 4

What is the study consensus on the usage of mannitol, dopamine, and fenoldopam for the purpose of renal protection in AAA repair cases?

Answer 4

All of the above drugs show inconclusive evidence for renal protection.

Question 5

What is used postoperatively for AAA repair pain?

Answer 5

Epidural catheter

Question 6

Why are epidural opioids preferred over LA in epidurals for AAA repair patients?

Answer 6

• LA’s are implicated in more hypotension and thus anterior spinal artery syndrome.

Question 7

What is anterior spinal artery syndrome?

Answer 7

Condition of paraplegia, back pain, loss of temperature and pain, and autonomic dysfunction below the level of aortic clamping.

Question 8

When can local anesthetics be utilized in an epidural for aortic repair?

Answer 8

After unclamping and stabilization of blood pressure

I.e. postoperatively.

Question 9

What major radicular artery comes off around T9 - T11?

Answer 9

Artery of Adamkiewicz

Question 10

What technique can be used to help prevent post-operative paraplegia from clamping affecting the artery of adamkiewicz?

Answer 10

• Spinal catheter draining CSF (less CSF = more room for hematoma formation, etc.)

Not a routine method.

Question 11

A clamp placed distal to the left subclavian results in a ___% decrease in renal blood flow.

Answer 11

90%

Question 12

A clamp placed infrarenal (below kidneys) will result in a ___% drop in renal flow.

Answer 12

30%

Though clamped below renal arteries, catecholamine release, metabolites, etc will effect renal flow.

Question 13

Is a full bypass dose of heparin required for left heart bypass for an aortic repair?

Answer 13

No, not required

Question 14

What technique is used for repair of a significant ascending aortic aneurysm?

Answer 14

DHCA (Deep Hypothermic Circulatory Arrest)

Question 15

What temperature is targeted for DHCA?

Answer 15

18 - 20° C

Question 16

How much is CO decreased to during ascending aortic aneurysm repair?

Answer 16

400 - 500 cc/min

Question 17

How long is the “safe” zone for DHCA?

Answer 17

30min

>40 min = brain injury.

Question 18

What is mortality for ascending aortic repairs requiring circulatory arrest?

Answer 18

10 - 15%

coagulopathies

Question 19

What is the “R” time in the following TEG?
What is this “R” time dependent on?

Answer 19

• Time from start of test to initial fibrin formation
• Dependent on clotting factors

Question 20

What is the “K” time in the following TEG?
What is this “K” time dependent on?

Answer 20

• Time from initial fibrin clot to to 20mm of clot strength
• Dependent on fibrinogen

Question 21

What is the α angle in the following TEG?
What is this α angle dependent on?

Answer 21

• Measures the rate of clot formation
• Dependent on fibrinogen

Question 22

What does MA stand for in the following TEG?
What is MA dependent on?

Answer 22

• MA = Maximum Amptidude (size & overal strength of fibrin clot)
• Dependent on platelets primarily (also a little fibrinogen).

Question 23

What does MA stand for in the following TEG?
What is MA dependent on?

Answer 23

• MA = Maximum Amplidude (size & overal strength of fibrin clot)
• Dependent on platelets primarily (also a little fibrinogen).

Question 24

What is the the LY30 on the following TEG?

Answer 24

• Percentage decrease in amplitude 30 minutes post MA.
• Showcases fibrinolysis

Question 25

What is a normal TEG "R" value?

Answer 25

4 - 8 min

Question 26

What is a normal TEG "K" value?

Answer 26

1 - 4 min

Question 27

What is a normal α-angle?

Answer 27

45 - 75°

Question 28

What is a normal TEG MA?

Answer 28

55 - 75 mm

Question 29

What is a normal LY30%?

Answer 29

0 - 8%

Question 30

What are some possible treatment options for the massively increased cardiac afterload from aortic clamping?

Answer 30

- ↑ Anesthetic (propofol or VAA) - Nitroglycerin or Nitroprusside

Question 31

What should be limited prior to aortic clamping in order to minimize a hyperdynamic cardiac state?

Answer 31

Fluids (less preload = less contractility = less strain on heart)

Question 32

What systemic change occurs from aortic unclamping?

Answer 32

Systemic Acidosis

Question 33

What hemodynamic changes occur during aortic unclamping?

Answer 33

- ↓ sBP - ↓ Contractility - ↓ SVR - ↓ preload - ↓ CO - ↓ pH **Essentially everything drops**.

Question 34

What is the treatment for aortic unclamping?

Answer 34

- ↓ Anesthetics - Fluids - Vasopressor boluses

Question 35

Does nitroglycerin primarily decrease preload or afterload?

Answer 35

Primarily preload (though some arterial vasodilation occurs as well).